Current client and server applications for the composition and delivery of electronic messages such as e-mail, peer-to-peer (P2P) messaging, short message service (SMS), and the like, allow users to define a text set that is automatically appended to the end of all messages sent from the user's communication device, whether a personal computer, handheld communication device, or the like. This automated signature may comprise the user's contact details, news items or announcements, or other information of interest to either the user or the recipient of the message.
For example, the user may define an automated signature cautioning the recipient of the confidential or privileged nature of the electronic communication. Alternatively, the automated signature may be defined to provide information about the type of encoding or encryption used in the message. As an example, if a message is signed using Secure Multipurpose Internet Mail Extension (S/MIME), the recipient will require a copy of the appropriate certificate in order to validate the digital S/MIME signature. Thus, the user may define an automated signature to read, “This message has been signed using S/MIME. If the signature appears to be invalid, you are probably missing my certificate authority's root certificate. Please contact me for information on how to download the root certificate.”
In practice, because an automated signature is appended to every message composed by the user, the content of the automated signature may be inaccurate given the context of the electronic message. If the user is sending an e-mail message to an individual within the same organization, it may be unnecessary to include a confidentiality notice in the automated signature. Or, if the user is sending merely a plaintext message, and not a digitally signed message, an automated signature providing information about obtaining a certificate authority's root certificate is irrelevant. Currently, the only means by which a predefined automated signature may be edited are either by manually editing the signature text, once appended to the electronic message, or by selecting another user profile with differently defined automated signature text. These solutions are inconvenient or impracticable.
In the first case, the messaging application must allow the user to edit the automated signature text at the same time the message is composed. This requires that the user remember to edit the automated signature text after making a decision to digitally sign or encrypt the message (or after making a decision not to digitally sign or encrypt the message); this first case also presupposes that the signature will be appended to the message at the user's communication device. If the messaging system is configured to append the automated signature to the message after the message is received by a message server, the user will not have an opportunity to edit the signature. In the second case, while some messaging applications may support multiple profiles for a single user, the user must remember to select the appropriate profile prior to composing the message.
Alternatively, the automated signature text may be defined to address all possible contingencies (for example, the text may read “This message may have been signed . . . ” instead of “This message has been signed . . . ”), but this may result in an inefficient use of resources, particularly if none of the contingencies apply to the message at hand. For example, if the message sent is merely a plaintext message without a digital signature or encryption, then any information provided about encoding or certificates would be superfluous; the size of the automated signature may even be larger than the content of the message itself.
Accordingly, it is desirable to provide a system and method for the automated selection and inclusion of automated signature text in an electronic message appropriate for the encoding method and/or recipient of the message. It is furthermore desirable to provide a system and method for defining automated signature text for use for different encoding methods or for classes of recipients.